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2018年12月24日星期一

新研究表示南極冰蓋可能很快崩潰 -- 而海水將會誇張地提升

新研究表示南極冰蓋可能很快崩潰 -- 而海水將會誇張地提升
New Research Says Antarctic Ice Sheet Could Collapse Soon--and Dramatically Raise the Seas

Earlier this year, we reported on scientists' warnings that Antarctica's ice sheets were hitting record lows, as well as news that all that melting ice was already beginning to impact Earth's sea levels. Now, a new study suggests that the West Antarctic ice shelf collapsed under similar conditions roughly 125,000 years ago—and it may happen again.

According to scientists involved with the study, gauging erosion in sediment samples taken near Antarctica caused them to notice a strange absence in the ge.n the sediments was previously crystal clear, suddenly seemed to disappear from the record. According to the leader of the study, Anders Carlson: "We don't see any sediments coming from the much larger West Antarctic Ice Sheet, which we'd interpret to mean that it was gone. It didn't have that erosive power anymore."

What makes this finding especially worrying is that the worldwide temperature during that ancient period was only 1 degree Celsius higher than it is today. According to Jeremy Shakun, a paleoclimatologist: "...the West Antarctic Ice Sheet might not need a huge nudge to budge...the big uptick in mass loss observed there in the past decade or two is perhaps the start of that process rather than a short-term blip."

After the collapse of the ancient ice sheet, it's estimated that sea levels rose about eight feet per century, maxing out at levels that were 20 to 30 feet higher than they are today. It's not clear how close an analogue this ancient sea-rise will be to today, but further research is planned to confirm that the West Antarctic ice sheet did indeed disappear 125,000 years ago, triggering a rise.

There have been a few potential solutions suggested so far, but many of them involve massive new 'geoengineering' projects, such as building a giant wall under the Antarctic ice to prop it up or spraying tons of chemicals into the atmosphere to artificially cool the planet by reflecting the Sun's rays. Though the latter has actually picked up some traction, its proponents have pointed out that we'd better start working on it soon—once the ice sheets begin to collapse, there will be no going back.


https://www.outerplaces.com/science/item/19190-antarctic-ice-sheet-collapse






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